Field of the Invention
The field of the invention is data processing, or, more specifically, methods, apparatus, and products for reducing power consumption in a multi-slice computer processor.
Description of Related Art
The development of the EDVAC computer system of 1948 is often cited as the beginning of the computer era. Since that time, computer systems have evolved into extremely complicated devices. Today's computers are much more sophisticated than early systems such as the EDVAC. Computer systems typically include a combination of hardware and software components, application programs, operating systems, processors, buses, memory, input/output devices, and so on. As advances in semiconductor processing and computer architecture push the performance of the computer higher and higher, more sophisticated computer software has evolved to take advantage of the higher performance of the hardware, resulting in computer systems today that are much more powerful than just a few years ago.
Modern computing systems can include one or more microprocessors. In current microprocessor design, the re-order buffer (‘ROB’) or the architected register file (‘ARF’) contain operand data that an instruction would need to access before it can be executed. In this ROB/ARF design, the ARF contains completed data (architected data), while the ROB contains in-flight data (i.e. data for instructions that have not been completed). In current design, the dispatching or issuing instructions will read the ROB and the ARF for its operands regardless the ROB/ARF data is available or not. If the data from the ROB/ARF is available, then the instruction can be executed. However, if the data from the ROB/ARF is not available because its producer has not written back the data, then the data is stale and not usable by the dispatching/issuing instruction. Reading stale data from the ROB/ARF Register Files consumes and wastes power.